Discharge patterns and duration tuning functions of the three representative units. A–C, Raster plots and mean PSTHs of 20 trials in response to tone bursts of different durations (10, 20, 40, 80, 160, and 320 ms). Shaded areas indicate stimulus duration. D–F, Mean driven rate as a function of stimulus duration. Dotted line shows the level of 2 SDs of the background firing rate.